Exemplary embodiments of the present invention relate to a primerless base painting composition for parts of a vehicle, a kit comprising the same, painted parts of a vehicle comprising the same, and a method for painting and varnishing parts of a vehicle using the same. More specifically, the present invention relates to a primerless base painting composition for the parts of a vehicle, a kit comprising the same, painted parts of a vehicle comprising the same, and a method for painting and varnishing parts of a vehicle using the same, which may keep physical properties of a paint film without a primer pre-treatment process at an equivalent or more and reduce the number of processes and save costs due to an absence of the primer pre-treatment process.
Parts of a vehicle are molded of polyolefin including polypropylene, and the like. Surfaces of Parts of a vehicle are painted and varnished with paints, and the like to improve an appearance and physical properties of the parts of a vehicle.
The typically painted parts of a vehicle are configured of a material for parts of a vehicle, a primer layer on the material for parts of a vehicle, a base coating layer on the primer layer, and a clear coating layer on the base coating layer. FIG. 2 is a cross-sectional view of typically painted parts of a vehicle. Referring to FIG. 2, the painted parts of a vehicle may include a material 10 for parts of a vehicle, a primer layer 40 on the material 10 for parts of a vehicle, a base coating layer 50 on the primer layer 40, and a clear coating layer 30 on the base coating layer 50. The base coating layer is a colored paint layer and the clear coating layer is a layer formed of a clear paint to provide a high gloss. A thickness of the primer layer may be 8 μm, a thickness of the base coating layer may be 20 μm, and a thickness of the clear coating layer may be 30 μm.
The material for parts of a vehicle is generally molded of polyolefin, including polypropylene, and the like. Generally, a polypropylene-based resin which is a non-polar material has been known as a material having poor adhesive property. Therefore, to increase the adhesion of the polypropylene-based resin, the primer layer is formed on the material for parts of a vehicle. The primer layer is essential to increase the adhesion between the material for parts of a vehicle and various coating layers and is generally made of a chlorinated polyolefin resin. The base coating layer is a coating layer which provides colors to the parts of a vehicle and includes an acrylic resin, a polyurethane resin, a pigment, and the like. The clear coating layer is to make an appearance of parts of a vehicle good, provide a high gloss to the parts of a vehicle, and enhance reliability of a paint film and includes an acrylic resin, a polyester resin, and a diisocyanate-based hardener including a 3-functional hexamethyldiisocyanate, and the like as a hardener.
As such, a method for painting and varnishing parts of a vehicle according to the related art performs three processes, that is, a process of forming the primer layer, a process of forming the base coating layer, and a process of forming the clear coating layer to cause an increase in process cost and a reduction in productivity and uses various volatile organic compounds for forming the primer layer including the chlorinated polyolefin resin, and the like to cause environmental issues.